Air brake system



- Oct. 18, 1938.\ I D. F sEARLE 2,133,580

' AIR BRAKE SYSTEM Filed July 19', 1937 FIG. I. FIG. 2[

INVENTOR:

DUDLEY F. SEARLE BY- 2 r [ATTORNEY Home... 18,1938 v A I 2,133,5

r UNITED STATES, PATENT OFFICE I 3, 80 .l g

AIR BRAKE sxs'rarr Dudley F. Seal-1e, omens, cam. Application July 19, 1931, se i ino. 154,469 -5 Claims. (01. abs-5o) invention relates to improvements in air 3 Fig, '1 is a diagrammatic view of-acontrol valve brake systems, and more partlcularlytograduconstructed in accordance with this invention atingcontrol valves therefor. shown in plan view connected to the essential- Among theobjects ofthis-inventiopis to proelements of a; conventional vacuum air brake 5 vide a control valve which will automatically vsystem which is shown in side elevation. 5

' maintain the brake power chamber ata constant Fig. 2 is an enlarged. vertical section taken pressure so that the brakes can be held applied: alon the line IIII in Fig. 1 of the control valve.

to any desired extent without variation fora I Fig.3 is a horizontal section taken alongthe prolonged period. line III III in Fig. 2 and showing the valvein Another object is to render the control valve an operating position. Q 10 capable of maintaining various pressures'in the 1 Fig. i isa similar view of the same in the posiv brake chamber which areaccurately proportional tion for full app ication of the brakes. to the distance that the control valve is vmoved- Fig. 5 is. a detail view in side elevationof the from neutral position. 1 valve plug showingthe tapered pressure control Another object is to provide a graduating congroove. l5

trolvalve which will automatically, maintain any n detail, the construction illustrated in the desired. pressure throughout the range from zero drawing comprises the valve body I secured. to a pressuretothe maximum pressure obtainable. suitable support 2 by the screws 3 asin 13713-1. It Anotherobje ct is toprovide unrestricted comhas the central opening 4 therethroug h which munication between the brake chamber and the tapers toward its upper end. The bosses! and I 20 pressure source for emergency operation of the extend from opposite sides of the valvebody and brakes. are internally threaded.

Another object is to provide a valve of simple The pipe V is screwed into the boss 5 and leads construction, inexpensive of manufacture, and to asource of sub-atmospheric air pressuresueh zo permanently reliable inoperation. as the intake motor manifold; 8 of an internal In prior valves of the present type, tapered combustion motor.. The pipe C is similarly congrooves were provided which cooperated with nected to the boss 6 and communicates with the boththe pressure supply port and the atmosbrake power chamber It) havingthe usual diap DQ The brake ber port was thus in phragm ll therein. 'I'heports l2 and I3 provide communication with boththe atmosphere and communication between the central opening I 30 the source of pressure 'to a variable extent. The and the pipes V and C respectively. :The ports existence of two variable quantities rendered it intersect the opening I at substantially 120 dedifficult to design prior valves so that the pres- 1 grees from each other.

sure maintained in.the brake chamber would be The port It is providedinthe-opposite side of 35. accurately proportional to the extent of the movethe opening 4 substantially equidistant from the ment of the control valve. It has been found, in ports I! and i3. It communicates with the paspractice; in thecase of sub-atmospheric pressage Awhich leads to the atmosphere through sure brakes for motor vehicles, that under this the bottom of the body I. Anair cleaner is prov teaching of "l is impossible to a vided for the air entering the passage l5.- vIt g 40 m a brake cylinder s u in the n e beconsists of theperforated cup l6 secured to the 40 tween e t and twe ty inches of vacuumbottom of the valve body-and containing the Broadly stated, the present invention consists, fibrous filtering material II. The perforated disk in part, of providing a tapered channel for coopl8 retains the: material II in place within the erating with the pressure port of a control valve, cup [6, '45. a'nd a groove of constant cross-sectional area for' The tapered valve plug I9 is a smooth sliding cooperating with the atmospheric port. fit withinthe opening 4.. It has the stem 20 pro- Other objects and advantages appear as this jecting upwardly therefrom. The manual operdescriptionprogresses. ating handle 2| has its hub 22 fixed on the stem In .the specification I and the accompanying 20 by means of the transversepin 23. The handle 50, drawing, the invention is disclosed in its pre- 2| may have a conventional friction pawl (not ferred form. It is, however, tobeunderstood that shown) cooperating with the notches 24, prothe invention is not limited to this form because vlded' on the body i, see, Fig. 1 to retain the modifications may be made within the purview handle in the position to whichit is moved by the of the claims following the description. operator. V i 55, In the oneshe'etof drawings: .The bottom of the hub 22 has the annular tional area as the ports l2, I3, and I4.

groove 2| therein. The marcel spring 26 confined in this groove expands against the top of the body I and draws the tapered plug l9 into flrm enuniform width and depth and extendsfrom the slot 21 in a clockwise direction and cooperates with the passage Il, see Fig. 3. v

The apparatus operates substantially as follows:. When the valve is in neutral position as shown in Fig. 2, the chamber II is maintained at atmospheric pressure "by air being free to flow from the atmospheric duct A, through the recess 21 registering'with the ports I I and ll, into the pipe C leading to the chamber.

To apply the brakes the handle 21 is manually moved to the right a distance depending upon the extent of brake application desired. This rotates the plug I 9 in a counterclockwise direction. The recess 21 passes out of registry'with the port II. The port It, however, remains in communication with the port II through the restricted groove 32. The end of the channel I0 moves into registry with the port i2.

Air flows at a limited rate from the port ll, past the restriction at 3| into the intake manitold I. The reduced pressure in the recess 21 causes air to flow thereinto from the atmosphere through the tapered channel 32. recess 21' then reaches an equilibrium pressure which depends upon the relative sizes of the air passages aflorded to the manifold 8, past the restriction 30, and from the atmosphere over the taperedchannel 32. The pressure in the power chamber It falls until it equals the equilibrium pressure in the recess 21. It then remains constant. .The brakes are thus applied and held applied to a constant extent.

This equilibrium pressure may 'be raised or lowered by moving the handle 21 to the-right or left respectively. This rotatesthe tapered channel In with respect to the port l2 thus either increasing or decreasing the size of the air passage therethrough with respect to the constant size of the opening through the groove 32. The groove 32 of constant cross sectional area throughout renders it possible to arrange the dimensions of the single tapered slot 30 to provide for accurate control of the brakes throughout, the

full range of operating pressures desired:

To apply the brakes fully, the handle 2| is moved to the extreme right. This moves the plug 19 into the position shown in Fig. 4, with the recess 21 registering with both the port II and the port i2. The groove 32 passes out of reg-- 'istry with the port It. This cuts or: the power chamber ill from communication with the atmosphere. The recess 21 provides unrestricted communication between the power chamber Ill and the manifold 8. The pressure in the chamber l0 immediately fallsto the subatmospheric pressure in the manifold, rapidly applying the brakes. to their fullest extentas required in emergency operation.

The brakes are released by simply moving the The handle II to the'extreme left. The plug I I then assumes the position shown in Fig. 2. The portion :33 covers the port I! thus closing 08 all communication to the intake manifold I. Free communication from the atmosphere to the chamber Illis provided by the recess 21. "This fully releases the brakes with rapidity.

It will be obvious to those skilled in the art that the tapered channel I. and the groove I! of constant cross sectional areas could be transposed without aflecting the operation of the valve.-

Having'thus described the invention, what is claimed and desired to be secured by Letters Patent is:

'1. In an air brake system having a source of pressure and a power chamber therein; a control valve body having three ports therein leading to said pressure source, said chamber, and the atmosphere respectively; and a movable valve mem- -ber adapted to cooperate with said ports and having a neutral and intermediate andextreme operative positions, said valve member having a recess therein adapted to provide unrestricted communication between the power chamber port and the atmospheric port respectively when said, 25

valve member is in said neutral position, said valve member having a greatly restricted groove therein adapted to provide communication between said atmospheric and said chamber port when said valve member is in an intermediate operative position and a second restricted groove arranged to be outof registry with said pressure port when said valve member is in the neutral position but being brought into registry therewith when said valve member is moved to an intermediate operative position, said valve member being arranged to bring the recess into a position to provide unrestricted communication between said pressure source port and said chamber port when said valve member is in: the ex treme operative position.

2. In an air brake system having a source of subatmospheric pressure and a power chamber therein; a control valve body having three ports therein connected to said pressure source, said chamber, and the atmosphere respectively; and a movable valve member adapted to cooperate with said ports and having neutral and operative positions, said valve member having'a recess'therein adapted to provide unrestricted communication between said atmospheric and chamber ports when said valve member is in said neutral position, said valve member having a restricted groove therein of constant cross sectional area and adapted to provide communication between saidatmospheric port and said chamber port respectively when said valve member is moved out of said neutral position, said valve member also having a tapered channel therein arranged so as to be out of registry with said pressure port when said valve member is in the neutral position and adapted to provide progressively less restricted communication between said pressure source port and said chamber port when said valve member is moved from neutral position.

3. In an air brake system having a source of subatmospheric pressure and a power chamber therein; a control valve body having three ports therein connected to said pressure source, said chamber, and the atmosphere respectively; a

valve member adapted to cooperate with said ports and having a neutral and an extreme operative position; said valve member havig a re cess therein adapted to provide unrestricted communication between said atmospheric and chamber P rts when said valve member is in said neutral position, said valve member having a restricted groove therein of constant cross sectional area adapted to provide communication between said atmospheric and chamber ports respectively when said valve member is moved out of said neutral position, said valve member also having a tapered channel arranged so as to be out oi! registry with said pressure port when said valve member is in said neutral position and adapted to provide communication between said pressure port and said chamber port when said valve member is in positions intermediate said neutral and said extreme operative position, said larger recess being arranged to provide unrestricted communication between said pressure source port and said chamber port when said valve member is in said extreme operative position.

4. In an air brake system having a source oi pressure and a power chamber therein; a control valve body having three ports therein leading to said pressure source, said chamber, and the atmosphere respectively; and a movable valve member adapted to cooperate with said ports and having neutral and operative positions, said valve member being arranged to provide communication between said atmospheric and chamber ports when said valve member is in said neutral position, said valve member having a restricted groove therein adapted to provide communication between said atmospheric port and said chamber port respectively when said valve member is moved into an operative position, said valve member-also having a channel therein tapered in both width and depth arranged so as to be out of registry with said pressure port when said valve member is in the neutral position and adapted to be brought into registry with said pressure source port when said'valve member is in an operative position.

5. In air air brake system having a source of sub-atmospheric pressure and a power chamber therein; a control valve body having an opening therein with three ports intersecting said opening and connected to said pressure source, said chamber, and the atmosphere respectively; and f a plug member rotatable within said opening and having a neutral and a variable operative position, said plug member having a restricted groove therein of constant cross sectional area adaptedto provide communication between the ports con nected with the atmosphere and said chamber respectively when said plug member is rotated out of said neutral position, said plug member having a larger recess therein adapted to provide communication between said atmospheric and said chamber ports when said plug member is in the neutral position, said plug member also having a tapered channel arranged so as to be out of registry with said pressure port when said plug member is in the neutral position and adapted to DUDLEY F. SEAFLE. 

